Grade and cross fall reference device for highway survey vehicles
First Claim
1. An artificial horizon device comprising a pitch and roll displacement gyroscope, an erection system for erecting the gyroscope relative to a gravitational reference, means for measuring changes of angular displacement of the device in a horizontal plane, means for calculating from said measured changes the centripetal acceleration of the device in said plane, and means calculating therefrom the cumulative magnitude of spurious erection resulting from said acceleration, to provide a correction to be applied to a roll displacement output of said displacement gyroscope.
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Accused Products
Abstract
In a highway survey vehicle, grade and cross fall measurements are made in relation to references established by a displacement type pitch and roll gyroscope with a gravity referenced erection system. Lateral acceleration of the vehicle is calculated independently and used to provide a correction for errors caused by spurious erection induced by such lateral acceleration, provided that such acceleration falls within certain limits such as to permit effective correction. The lateral acceleration may be calculated from measured rates of displacement and change of the direction of the vehicle.
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Citations
9 Claims
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1. An artificial horizon device comprising a pitch and roll displacement gyroscope, an erection system for erecting the gyroscope relative to a gravitational reference, means for measuring changes of angular displacement of the device in a horizontal plane, means for calculating from said measured changes the centripetal acceleration of the device in said plane, and means calculating therefrom the cumulative magnitude of spurious erection resulting from said acceleration, to provide a correction to be applied to a roll displacement output of said displacement gyroscope.
- 2. A grade and cross fall reference device for a road vehicle comprising a pitch and roll displacement gyroscope, an erection system for erecting the gyroscope relative to a gravitational reference, means for measuring changes of angular direction of the vehicle in a horizontal plane, means for calculating from said measured changes the centripetal acceleration of the vehicle in said plane, and means calculating therefrom the cumulative magnitude of spurious erection resulting from said acceleration, to provide a correction to be applied to a roll displacement output of said displacement gyroscope to provide a cross fall reference.
Specification